err.no Git - linux-2.6/blob - kernel/power/swap.c

   1 /*
   2  * linux/kernel/power/swap.c
   3  *
   4  * This file provides functions for reading the suspend image from
   5  * and writing it to a swap partition.
   6  *
   7  * Copyright (C) 1998,2001-2005 Pavel Machek <pavel@suse.cz>
   8  * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
   9  *
  10  * This file is released under the GPLv2.
  11  *
  12  */
  13
  14 #include <linux/module.h>
  15 #include <linux/smp_lock.h>
  16 #include <linux/file.h>
  17 #include <linux/utsname.h>
  18 #include <linux/version.h>
  19 #include <linux/delay.h>
  20 #include <linux/bitops.h>
  21 #include <linux/genhd.h>
  22 #include <linux/device.h>
  23 #include <linux/buffer_head.h>
  24 #include <linux/bio.h>
  25 #include <linux/swap.h>
  26 #include <linux/swapops.h>
  27 #include <linux/pm.h>
  28
  29 #include "power.h"
  30
  31 extern char resume_file[];
  32
  33 #define SWSUSP_SIG      "S1SUSPEND"
  34
  35 static struct swsusp_header {
  36         char reserved[PAGE_SIZE - 20 - sizeof(swp_entry_t)];
  37         swp_entry_t image;
  38         char    orig_sig[10];
  39         char    sig[10];
  40 } __attribute__((packed, aligned(PAGE_SIZE))) swsusp_header;
  41
  42 /*
  43  * Saving part...
  44  */
  45
  46 static unsigned short root_swap = 0xffff;
  47
  48 static int mark_swapfiles(swp_entry_t start)
  49 {
  50         int error;
  51
  52         rw_swap_page_sync(READ,
  53                           swp_entry(root_swap, 0),
  54                           virt_to_page((unsigned long)&swsusp_header));
  55         if (!memcmp("SWAP-SPACE",swsusp_header.sig, 10) ||
  56             !memcmp("SWAPSPACE2",swsusp_header.sig, 10)) {
  57                 memcpy(swsusp_header.orig_sig,swsusp_header.sig, 10);
  58                 memcpy(swsusp_header.sig,SWSUSP_SIG, 10);
  59                 swsusp_header.image = start;
  60                 error = rw_swap_page_sync(WRITE,
  61                                           swp_entry(root_swap, 0),
  62                                           virt_to_page((unsigned long)
  63                                                        &swsusp_header));
  64         } else {
  65                 pr_debug("swsusp: Partition is not swap space.\n");
  66                 error = -ENODEV;
  67         }
  68         return error;
  69 }
  70
  71 /**
  72  *      swsusp_swap_check - check if the resume device is a swap device
  73  *      and get its index (if so)
  74  */
  75
  76 static int swsusp_swap_check(void) /* This is called before saving image */
  77 {
  78         int res = swap_type_of(swsusp_resume_device);
  79
  80         if (res >= 0) {
  81                 root_swap = res;
  82                 return 0;
  83         }
  84         return res;
  85 }
  86
  87 /**
  88  *      write_page - Write one page to given swap location.
  89  *      @buf:           Address we're writing.
  90  *      @offset:        Offset of the swap page we're writing to.
  91  */
  92
  93 static int write_page(void *buf, unsigned long offset)
  94 {
  95         swp_entry_t entry;
  96         int error = -ENOSPC;
  97
  98         if (offset) {
  99                 entry = swp_entry(root_swap, offset);
 100                 error = rw_swap_page_sync(WRITE, entry, virt_to_page(buf));
 101         }
 102         return error;
 103 }
 104
 105 /*
 106  *      The swap map is a data structure used for keeping track of each page
 107  *      written to a swap partition.  It consists of many swap_map_page
 108  *      structures that contain each an array of MAP_PAGE_SIZE swap entries.
 109  *      These structures are stored on the swap and linked together with the
 110  *      help of the .next_swap member.
 111  *
 112  *      The swap map is created during suspend.  The swap map pages are
 113  *      allocated and populated one at a time, so we only need one memory
 114  *      page to set up the entire structure.
 115  *
 116  *      During resume we also only need to use one swap_map_page structure
 117  *      at a time.
 118  */
 119
 120 #define MAP_PAGE_ENTRIES        (PAGE_SIZE / sizeof(long) - 1)
 121
 122 struct swap_map_page {
 123         unsigned long           entries[MAP_PAGE_ENTRIES];
 124         unsigned long           next_swap;
 125 };
 126
 127 /**
 128  *      The swap_map_handle structure is used for handling swap in
 129  *      a file-alike way
 130  */
 131
 132 struct swap_map_handle {
 133         struct swap_map_page *cur;
 134         unsigned long cur_swap;
 135         struct bitmap_page *bitmap;
 136         unsigned int k;
 137 };
 138
 139 static void release_swap_writer(struct swap_map_handle *handle)
 140 {
 141         if (handle->cur)
 142                 free_page((unsigned long)handle->cur);
 143         handle->cur = NULL;
 144         if (handle->bitmap)
 145                 free_bitmap(handle->bitmap);
 146         handle->bitmap = NULL;
 147 }
 148
 149 static void show_speed(struct timeval *start, struct timeval *stop,
 150                         unsigned nr_pages, char *msg)
 151 {
 152         s64 elapsed_centisecs64;
 153         int centisecs;
 154         int k;
 155         int kps;
 156
 157         elapsed_centisecs64 = timeval_to_ns(stop) - timeval_to_ns(start);
 158         do_div(elapsed_centisecs64, NSEC_PER_SEC / 100);
 159         centisecs = elapsed_centisecs64;
 160         if (centisecs == 0)
 161                 centisecs = 1;  /* avoid div-by-zero */
 162         k = nr_pages * (PAGE_SIZE / 1024);
 163         kps = (k * 100) / centisecs;
 164         printk("%s %d kbytes in %d.%02d seconds (%d.%02d MB/s)\n", msg, k,
 165                         centisecs / 100, centisecs % 100,
 166                         kps / 1000, (kps % 1000) / 10);
 167 }
 168
 169 static int get_swap_writer(struct swap_map_handle *handle)
 170 {
 171         handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL);
 172         if (!handle->cur)
 173                 return -ENOMEM;
 174         handle->bitmap = alloc_bitmap(count_swap_pages(root_swap, 0));
 175         if (!handle->bitmap) {
 176                 release_swap_writer(handle);
 177                 return -ENOMEM;
 178         }
 179         handle->cur_swap = alloc_swap_page(root_swap, handle->bitmap);
 180         if (!handle->cur_swap) {
 181                 release_swap_writer(handle);
 182                 return -ENOSPC;
 183         }
 184         handle->k = 0;
 185         return 0;
 186 }
 187
 188 static int swap_write_page(struct swap_map_handle *handle, void *buf)
 189 {
 190         int error;
 191         unsigned long offset;
 192
 193         if (!handle->cur)
 194                 return -EINVAL;
 195         offset = alloc_swap_page(root_swap, handle->bitmap);
 196         error = write_page(buf, offset);
 197         if (error)
 198                 return error;
 199         handle->cur->entries[handle->k++] = offset;
 200         if (handle->k >= MAP_PAGE_ENTRIES) {
 201                 offset = alloc_swap_page(root_swap, handle->bitmap);
 202                 if (!offset)
 203                         return -ENOSPC;
 204                 handle->cur->next_swap = offset;
 205                 error = write_page(handle->cur, handle->cur_swap);
 206                 if (error)
 207                         return error;
 208                 memset(handle->cur, 0, PAGE_SIZE);
 209                 handle->cur_swap = offset;
 210                 handle->k = 0;
 211         }
 212         return 0;
 213 }
 214
 215 static int flush_swap_writer(struct swap_map_handle *handle)
 216 {
 217         if (handle->cur && handle->cur_swap)
 218                 return write_page(handle->cur, handle->cur_swap);
 219         else
 220                 return -EINVAL;
 221 }
 222
 223 /**
 224  *      save_image - save the suspend image data
 225  */
 226
 227 static int save_image(struct swap_map_handle *handle,
 228                       struct snapshot_handle *snapshot,
 229                       unsigned int nr_to_write)
 230 {
 231         unsigned int m;
 232         int ret;
 233         int error = 0;
 234         int nr_pages;
 235         struct timeval start;
 236         struct timeval stop;
 237
 238         printk("Saving image data pages (%u pages) ...     ", nr_to_write);
 239         m = nr_to_write / 100;
 240         if (!m)
 241                 m = 1;
 242         nr_pages = 0;
 243         do_gettimeofday(&start);
 244         do {
 245                 ret = snapshot_read_next(snapshot, PAGE_SIZE);
 246                 if (ret > 0) {
 247                         error = swap_write_page(handle, data_of(*snapshot));
 248                         if (error)
 249                                 break;
 250                         if (!(nr_pages % m))
 251                                 printk("\b\b\b\b%3d%%", nr_pages / m);
 252                         nr_pages++;
 253                 }
 254         } while (ret > 0);
 255         do_gettimeofday(&stop);
 256         if (!error)
 257                 printk("\b\b\b\bdone\n");
 258         show_speed(&start, &stop, nr_to_write, "Wrote");
 259         return error;
 260 }
 261
 262 /**
 263  *      enough_swap - Make sure we have enough swap to save the image.
 264  *
 265  *      Returns TRUE or FALSE after checking the total amount of swap
 266  *      space avaiable from the resume partition.
 267  */
 268
 269 static int enough_swap(unsigned int nr_pages)
 270 {
 271         unsigned int free_swap = count_swap_pages(root_swap, 1);
 272
 273         pr_debug("swsusp: free swap pages: %u\n", free_swap);
 274         return free_swap > (nr_pages + PAGES_FOR_IO +
 275                 (nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE);
 276 }
 277
 278 /**
 279  *      swsusp_write - Write entire image and metadata.
 280  *
 281  *      It is important _NOT_ to umount filesystems at this point. We want
 282  *      them synced (in case something goes wrong) but we DO not want to mark
 283  *      filesystem clean: it is not. (And it does not matter, if we resume
 284  *      correctly, we'll mark system clean, anyway.)
 285  */
 286
 287 int swsusp_write(void)
 288 {
 289         struct swap_map_handle handle;
 290         struct snapshot_handle snapshot;
 291         struct swsusp_info *header;
 292         int error;
 293
 294         if ((error = swsusp_swap_check())) {
 295                 printk(KERN_ERR "swsusp: Cannot find swap device, try swapon -a.\n");
 296                 return error;
 297         }
 298         memset(&snapshot, 0, sizeof(struct snapshot_handle));
 299         error = snapshot_read_next(&snapshot, PAGE_SIZE);
 300         if (error < PAGE_SIZE)
 301                 return error < 0 ? error : -EFAULT;
 302         header = (struct swsusp_info *)data_of(snapshot);
 303         if (!enough_swap(header->pages)) {
 304                 printk(KERN_ERR "swsusp: Not enough free swap\n");
 305                 return -ENOSPC;
 306         }
 307         error = get_swap_writer(&handle);
 308         if (!error) {
 309                 unsigned long start = handle.cur_swap;
 310                 error = swap_write_page(&handle, header);
 311                 if (!error)
 312                         error = save_image(&handle, &snapshot,
 313                                         header->pages - 1);
 314                 if (!error) {
 315                         flush_swap_writer(&handle);
 316                         printk("S");
 317                         error = mark_swapfiles(swp_entry(root_swap, start));
 318                         printk("|\n");
 319                 }
 320         }
 321         if (error)
 322                 free_all_swap_pages(root_swap, handle.bitmap);
 323         release_swap_writer(&handle);
 324         return error;
 325 }
 326
 327 /*
 328  *      Using bio to read from swap.
 329  *      This code requires a bit more work than just using buffer heads
 330  *      but, it is the recommended way for 2.5/2.6.
 331  *      The following are to signal the beginning and end of I/O. Bios
 332  *      finish asynchronously, while we want them to happen synchronously.
 333  *      A simple atomic_t, and a wait loop take care of this problem.
 334  */
 335
 336 static atomic_t io_done = ATOMIC_INIT(0);
 337
 338 static int end_io(struct bio *bio, unsigned int num, int err)
 339 {
 340         if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) {
 341                 printk(KERN_ERR "I/O error reading swsusp image.\n");
 342                 return -EIO;
 343         }
 344         atomic_set(&io_done, 0);
 345         return 0;
 346 }
 347
 348 static struct block_device *resume_bdev;
 349
 350 /**
 351  *      submit - submit BIO request.
 352  *      @rw:    READ or WRITE.
 353  *      @off    physical offset of page.
 354  *      @page:  page we're reading or writing.
 355  *
 356  *      Straight from the textbook - allocate and initialize the bio.
 357  *      If we're writing, make sure the page is marked as dirty.
 358  *      Then submit it and wait.
 359  */
 360
 361 static int submit(int rw, pgoff_t page_off, void *page)
 362 {
 363         int error = 0;
 364         struct bio *bio;
 365
 366         bio = bio_alloc(GFP_ATOMIC, 1);
 367         if (!bio)
 368                 return -ENOMEM;
 369         bio->bi_sector = page_off * (PAGE_SIZE >> 9);
 370         bio->bi_bdev = resume_bdev;
 371         bio->bi_end_io = end_io;
 372
 373         if (bio_add_page(bio, virt_to_page(page), PAGE_SIZE, 0) < PAGE_SIZE) {
 374                 printk("swsusp: ERROR: adding page to bio at %ld\n",page_off);
 375                 error = -EFAULT;
 376                 goto Done;
 377         }
 378
 379         atomic_set(&io_done, 1);
 380         submit_bio(rw | (1 << BIO_RW_SYNC), bio);
 381         while (atomic_read(&io_done))
 382                 yield();
 383         if (rw == READ)
 384                 bio_set_pages_dirty(bio);
 385  Done:
 386         bio_put(bio);
 387         return error;
 388 }
 389
 390 static int bio_read_page(pgoff_t page_off, void *page)
 391 {
 392         return submit(READ, page_off, page);
 393 }
 394
 395 static int bio_write_page(pgoff_t page_off, void *page)
 396 {
 397         return submit(WRITE, page_off, page);
 398 }
 399
 400 /**
 401  *      The following functions allow us to read data using a swap map
 402  *      in a file-alike way
 403  */
 404
 405 static void release_swap_reader(struct swap_map_handle *handle)
 406 {
 407         if (handle->cur)
 408                 free_page((unsigned long)handle->cur);
 409         handle->cur = NULL;
 410 }
 411
 412 static int get_swap_reader(struct swap_map_handle *handle,
 413                                       swp_entry_t start)
 414 {
 415         int error;
 416
 417         if (!swp_offset(start))
 418                 return -EINVAL;
 419         handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_ATOMIC);
 420         if (!handle->cur)
 421                 return -ENOMEM;
 422         error = bio_read_page(swp_offset(start), handle->cur);
 423         if (error) {
 424                 release_swap_reader(handle);
 425                 return error;
 426         }
 427         handle->k = 0;
 428         return 0;
 429 }
 430
 431 static int swap_read_page(struct swap_map_handle *handle, void *buf)
 432 {
 433         unsigned long offset;
 434         int error;
 435
 436         if (!handle->cur)
 437                 return -EINVAL;
 438         offset = handle->cur->entries[handle->k];
 439         if (!offset)
 440                 return -EFAULT;
 441         error = bio_read_page(offset, buf);
 442         if (error)
 443                 return error;
 444         if (++handle->k >= MAP_PAGE_ENTRIES) {
 445                 handle->k = 0;
 446                 offset = handle->cur->next_swap;
 447                 if (!offset)
 448                         release_swap_reader(handle);
 449                 else
 450                         error = bio_read_page(offset, handle->cur);
 451         }
 452         return error;
 453 }
 454
 455 /**
 456  *      load_image - load the image using the swap map handle
 457  *      @handle and the snapshot handle @snapshot
 458  *      (assume there are @nr_pages pages to load)
 459  */
 460
 461 static int load_image(struct swap_map_handle *handle,
 462                       struct snapshot_handle *snapshot,
 463                       unsigned int nr_pages)
 464 {
 465         unsigned int m;
 466         int ret;
 467         int error = 0;
 468
 469         printk("Loading image data pages (%u pages) ...     ", nr_pages);
 470         m = nr_pages / 100;
 471         if (!m)
 472                 m = 1;
 473         nr_pages = 0;
 474         do {
 475                 ret = snapshot_write_next(snapshot, PAGE_SIZE);
 476                 if (ret > 0) {
 477                         error = swap_read_page(handle, data_of(*snapshot));
 478                         if (error)
 479                                 break;
 480                         if (!(nr_pages % m))
 481                                 printk("\b\b\b\b%3d%%", nr_pages / m);
 482                         nr_pages++;
 483                 }
 484         } while (ret > 0);
 485         if (!error) {
 486                 printk("\b\b\b\bdone\n");
 487                 if (!snapshot_image_loaded(snapshot))
 488                         error = -ENODATA;
 489         }
 490         return error;
 491 }
 492
 493 int swsusp_read(void)
 494 {
 495         int error;
 496         struct swap_map_handle handle;
 497         struct snapshot_handle snapshot;
 498         struct swsusp_info *header;
 499
 500         if (IS_ERR(resume_bdev)) {
 501                 pr_debug("swsusp: block device not initialised\n");
 502                 return PTR_ERR(resume_bdev);
 503         }
 504
 505         memset(&snapshot, 0, sizeof(struct snapshot_handle));
 506         error = snapshot_write_next(&snapshot, PAGE_SIZE);
 507         if (error < PAGE_SIZE)
 508                 return error < 0 ? error : -EFAULT;
 509         header = (struct swsusp_info *)data_of(snapshot);
 510         error = get_swap_reader(&handle, swsusp_header.image);
 511         if (!error)
 512                 error = swap_read_page(&handle, header);
 513         if (!error)
 514                 error = load_image(&handle, &snapshot, header->pages - 1);
 515         release_swap_reader(&handle);
 516
 517         blkdev_put(resume_bdev);
 518
 519         if (!error)
 520                 pr_debug("swsusp: Reading resume file was successful\n");
 521         else
 522                 pr_debug("swsusp: Error %d resuming\n", error);
 523         return error;
 524 }
 525
 526 /**
 527  *      swsusp_check - Check for swsusp signature in the resume device
 528  */
 529
 530 int swsusp_check(void)
 531 {
 532         int error;
 533
 534         resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ);
 535         if (!IS_ERR(resume_bdev)) {
 536                 set_blocksize(resume_bdev, PAGE_SIZE);
 537                 memset(&swsusp_header, 0, sizeof(swsusp_header));
 538                 if ((error = bio_read_page(0, &swsusp_header)))
 539                         return error;
 540                 if (!memcmp(SWSUSP_SIG, swsusp_header.sig, 10)) {
 541                         memcpy(swsusp_header.sig, swsusp_header.orig_sig, 10);
 542                         /* Reset swap signature now */
 543                         error = bio_write_page(0, &swsusp_header);
 544                 } else {
 545                         return -EINVAL;
 546                 }
 547                 if (error)
 548                         blkdev_put(resume_bdev);
 549                 else
 550                         pr_debug("swsusp: Signature found, resuming\n");
 551         } else {
 552                 error = PTR_ERR(resume_bdev);
 553         }
 554
 555         if (error)
 556                 pr_debug("swsusp: Error %d check for resume file\n", error);
 557
 558         return error;
 559 }
 560
 561 /**
 562  *      swsusp_close - close swap device.
 563  */
 564
 565 void swsusp_close(void)
 566 {
 567         if (IS_ERR(resume_bdev)) {
 568                 pr_debug("swsusp: block device not initialised\n");
 569                 return;
 570         }
 571
 572         blkdev_put(resume_bdev);
 573 }